The present invention relates in general to window sash locks, and in particular to a rotating lever-style sash lock actuator for a multi-point or single point window locking system.
Conventionally, windows, such as casement or awning windows, are locked by manipulation of a lock actuator handle which causes corresponding motion in a catch. The actuator is affixed to a window frame so that the catch engages a keeper on a corresponding section of a movable window sash to securely hold the sash against the frame. Where only one keeper on the sash is engaged by a catch, the locking mechanism is referred to as a xe2x80x9csingle-pointxe2x80x9d locking mechanism.
Also known in the art are xe2x80x9cmulti-pointxe2x80x9d locking mechanisms, wherein operation of an actuator handle causes a plurality of catches to respectively engage a plurality of keepers at spaced locations on the sash. Such systems may include a tie bar assembly wherein operation of the actuator handle causes translation of a tie bar disposed on the window frame. As the sash approaches a closed position, translation of the tie bar causes engagement of a plurality of lock rollers/catches disposed on the tie bar with respective keepers on the sash, thereby locking the window.
It has been recognized that there are several features of a window sash lock which are particularly desirable, and which prior art actuators have not displayed. One desirable feature is smooth operation of the actuator for allowing facile locking with an even and non-excessive force. Due to the interaction of moving parts in conventional window locks, however, prior art lock actuators generally require abrupt changes in force required at the handle. These changes in force are imparted to the user during operation. In addition to being uncomfortable for a user, the substantial required force and uneven nature in which the force is experienced, can cause premature mechanical failure of the lock mechanism.
Another important feature of a window sash lock actuator is forced entry (xe2x80x9cpickxe2x80x9d) resistance. To prevent the lock from being disengaged from outside of the sash, protection of the internal mechanism of the lock actuator is necessary. Several approaches to pick resistance have been attempted in prior art actuators. Unfortunately, however, such approaches have resulted in cumbersome and expensive designs. In addition, prior art designs have generally failed to provide efficient and cost-effective pick resistance in a xe2x80x9cnon-handedxe2x80x9d actuator. A non-handed actuator is an actuator which allows lock operation regardless of the side of the window on which the actuator is mounted. Thus, in a non-handed actuator movement of the actuator handle in either direction of rotation may cause equal corresponding opposite movement in the catch or lock rollers.
Another desirable feature of a sash lock actuator is facile conversion of the actuator from a multi-point to a single-point actuator, and vice-versa. In prior art designs, the actuator has been particularly adapted to facilitate either multi-point mechanisms or single-point mechanisms. Manufacturing and installation efficiency is, however, improved by providing a single actuator which may be readily modified to accommodate either mechanism. This construction positively impacts window manufacturers in at least two ways: (1) it allows for reduced manufacturing and window preparation costs; and (2) it provides aesthetic enhancement since the lock has identical appearance in both multi-point and single point configuration, thereby providing a consistent and attractive appearance on both casement and awning windows.
Accordingly, there is a need in the art for an efficient and reliable sash lock actuator which allows for smooth and even lock actuation. There is also a need in the art for an efficient and reliable sash lock actuator which is pick-resistant and non-handed. There is also a need in the art for an efficient and reliable sash lock actuator which is convertible from multi-point to single point operation and vice-versa. There is a further need in the art for a sash lock actuator which offers consistent hardware application and appearance on a window.
Thus, the present invention is organized about the concept of providing an efficient and reliable sash lock actuator which exhibits smooth and even lock actuation., and which is pick-resistant, non-handed, and convertible from multi-point to single point operation. The actuator includes a housing with a pivot opening therein, which may be defined by portions of a separate cover and a base. An actuator handle has a pivot pin extending from an end thereof for connecting the handle to a crank which includes a drive pin. The handle is assembled to the housing with the pivot pin extending through the pivot opening. A bushing may be disposed between the pivot pin and the pivot opening, e.g., between the portions of the cover and base forming the pivot opening, to take up tolerances between the parts and provide smooth handle rotation.
The drive pin on the crank extends into a drive slot on a slider which translates within the housing to actuate a window locking mechanism. The drive slot is generally pear-shaped with, preferably symmetrical, opposed curved sidewalls along which the drive pin rides during rotation of the handle. The shape of the drive slot allows for smooth handle rotation, and the symmetry of the curved sidewalls allows the actuator to be non-handed for positioning on either side of a window frame. The slider may further include one or more fulcrum tabs disposed on a top thereof adjacent opposite sides of the drive slot for contacting a side surface of the crank during rotation of the handle. The fulcrum tabs provide mechanical advantage during rotation of the handle for forcing the slider to translate within the housing.
A spring is disposed within the housing for providing a detent function and for providing pick-resistance. The spring has a bowed middle portion which extends beneath the slider and identical ends which extend above the slider at each side thereof. Depending on the direction of handle rotation, one end of the spring provides the detent function by biasing the drive pin against one of the slider side walls. The other end extends upward to provide a physical barrier between a slot in the base portion of the housing and the crank, handle, and bushing. The physical barrier in combination with the cover, which is preferably closed on three sides, prevents the use of a xe2x80x9cpick-toolxe2x80x9d for providing pick resistance.
Finally, the actuator may be provided with an optional single-point slider extension. The single point extension may be disposed on the slider, either integrally or as a separate part, for directing a latch of a single-point locking mechanism into a latch opening in the extension during rotation of the handle. The latch opening may be defined by a pair of symmetrically curved arms which force the latch into the opening, and which provide non-handedness.
In particular, a sash lock actuator in accordance with the present invention may generally include a housing having a pivot opening therein and a pivot pin disposed at least partially within the pivot opening. The pivot pin has an actuator handle extending from a first end thereof and a crank extending from a second end thereof. The crank may be disposed at least partially within an interior cavity of the housing. A drive pin extends from a distal end of the crank and into a drive slot of a slider. The slider may have a first end disposed at least partially within the interior cavity and a second end adapted for engaging the locking mechanism. Upon rotation of the handle in a first direction, the slider is forced linearly relative to the housing in a second direction by engagement of the drive pin with a side wall of the slider.
According to one aspect of the invention, the drive slot may be defined by opposed curved side walls, the side walls curving inward from a relatively wide bottom of the slot and then outward to form a relatively narrow top of the slot. This slot geometry allows for smooth and even torque at the handle for operating the actuator.
According to another aspect of the invention, the slider may further include at least one fulcrum tab extending from a top thereof, the fulcrum tab being positioned on the slider for contacting a side surface of the crank for providing mechanical advantage upon rotation of the handle. In one embodiment, the slider may have first and second fulcrum tabs extending from a top thereof, the fulcrum tabs being positioned adjacent opposite sides of the slot, whereby upon rotation of the handle a side surface of the crank contacts one of the fulcrum tabs.
According to a further aspect of the invention, the actuator may include a spring disposed within the interior cavity. The spring may have a middle portion extending beneath the slider and first and second ends extending above a top surface of the slider. Upon rotation of the handle, the spring contacts the slider and moves linearly within the cavity with the slider. Upon maximum rotation of the handle in the first direction, the first end of the spring contacts an interior surface of the housing to bias the slider in a direction opposite to the second direction, the spring thereby forcing the drive pin against one of the curved side walls for detenting rotation of the handle in a direction opposite to the first direction. Also, with maximum rotation of the handle in the first direction, the second end of the spring is disposed adjacent the first end of the crank, the spring thereby forming a barrier between an opening in the housing through which the slider extends and the first end of the crank and the pivot pin. In one embodiment, the first and second ends of the spring may include a first flat portion, an upwardly extending angular portion extending from a first end of the first flat portion, an upwardly extending portion extending form an end of the angular portion, and a downwardly extending portion extending from a second end of the first flat portion. At least one of the downwardly extending portions is positioned to contact a side surface of the slider to cause linear movement of the spring with movement of the slider.
The housing of the actuator may comprise a cover and a base, the cover having portions defining a first portion of the pivot opening and the base having portions defining a second portion of the pivot opening. The base mates with the cover for forming the housing with the first and second portions of the pivot openings mating to form the pivot opening. The cover may have a top side wall having the portions defining the first portion of the pivot opening, a bottom side wall, an end side wall, and an open end. The base may have a slot therein, the base being adapted to mate with the housing for closing the open end with at least a portion of the slider extending through the slot. Also, the slider may have a slider guide rail extending therefrom, the slider guide rail being disposed in a slider guide rail slot defined by a shelf formed in an interior surface of the cover and an end surface of the base.
A bushing may be disposed between the pivot pin and the pivot opening for taking up tolerances between the pivot pin and the pivot opening and thereby facilitating smooth handle rotation. The bushing may include first and second halves joined at a hinge point. The first and second halves may have a partially cylindrical portion with a radially extending flange at a top of the cylindrical portion.
Advantageously, the slider may include a pair of legs defining a slot for engaging the locking mechanism, e.g., a multi-point locking mechanism, or it may include a single-point extension adapted for engaging a single-point locking mechanism. The single point extension may have a pair of arms and a latch opening for receiving a single point latch. Each of the arms may have a curved end surface for contacting the single point latch and directing the single point latch into the latch opening upon rotation of the handle.